A noteworthy application of reservoir-and-filter systems is use in blood and other biological fluid processing. For example, suctioning of blood away from surgical sites may be a high throughput operation if much fluid is quickly generated.
Many state-of-the-art reservoir-and-filter systems are designed having an essentially planar filter disposed so as to divide the reservoir into separated portions. A first portion is intended for containing unfiltered fluid derived from a source while the other portion holds filtrate. Common practice is to orient the filter so that the portions are laterally adjacent to one another with the filter surface situated perpendicular to the force of gravity. Fluid is urged into the reservoir by applying a partial vacuum and passes through the planar filter after enough fluid has been collected in the resevoir to create sufficient head pressure to force the fluid through the filter. Necessarily, such a filter will clog during high throughput usage as there are limited or no safe mechanisms for detaching impurities from the filter during operation. Clogging normally occurs, due to gravity, at the lowest portion of the filter and, with time, reduces the effective operational filtration area and traps a volume of unfiltered fluid. Gradually, the filter will tend to clog at higher and higher levels and trap greater volumes of unfiltered fluid. The ability to efficiently filter the fluid will, with time, be compromised.